给定一个仅包含0-9
的字符串和一个目标值,返回在数字之间添加了二元运算符(不是一元的) +
、-
或*
之后所有能得到目标值的情况。
例如:
"123", 6 -> ["1+2+3", "1*2*3"]
"232", 8 -> ["2*3+2", "2+3*2"]
"105", 5 -> ["1*0+5","10-5"]
"00", 0 -> ["0+0", "0-0", "0*0"]
"3456237490", 9191 -> []
#coding=utf-8
import itertools
import reclass Solution(object):
def addOperators(self, num, target):
if num:
count = len(num)-1
rnum = num[-1] s = "['','+','-','*'],"
ss = ""
for c in range(count):
ss += s ls = []
for item in itertools.product(*eval(ss[0:-1])):
zty = ''.join(list(itertools.chain.from_iterable(zip(list(num),item))))+rnum
if eval(zty) != target or re.match(r".*([\+\-\*]0)\d.*",zty,re.M|re.I):
continue
else:
ls.append(zty)
return ls return []print Solution().addOperators("", 5)